Half a century ago we saw the spark of powerful ideas that changed the face of America. Some became legislation, such as the War on Poverty. Others became potent cultural trends, like the sexual revolution. Less noticed but no less impactful was the onset of a radical change in our nation’s demographic makeup.

That millions of immigrants, the majority from Latin America, began arriving just as the United States was being hit by a social and cultural tornado receives surprisingly little analysis. This whirlwind, after all, ripped up norms that had been in place for generations.

These new immigrants had no memory of what the country had been like. In the media, in schools and in entertainment, they began to hear dubious reinterpretations of America and a denigration of traditional values. For many of them, “assimilation” meant adopting the emerging standards of a rapidly evolving country.

We'll soon mark the 50th anniversaries of the two major changes that brought this wave of new immigrants. On Dec. 1, 1964, Congress allowed the Bracero guest worker program to expire. The economic need for these workers didn’t go away, however, so illegal immigrants began streaming in – hundreds of thousands annually, for decades. Unlike under Bracero, these were not circular migrants; they stayed.

On Oct. 3 the following year, President Lyndon B. Johnson signed the Immigration and Nationality Act. Supporters like President John F. Kennedy had said the change would benefit primarily Southern Europeans, but it was Latin Americans who experienced the biggest gains. Close to 25 million of them have legally immigrated here since 1965, including my family and me.

These legal and illegal immigrants, and their progeny, spearheaded a demographic tsunami. Hispanics – a label the federal bureaucracy created in the 1970s for the express purpose of affirmative action – went from just about 3 percent of the American population in 1960 to 16 percent today.

And they are expected to account for about one third of the population by mid-century. Half of the demographic growth so far this century has been Hispanic.

Unless conservatives can share their message with these new Americans, they will encounter electoral difficulties and won’t be able to enact their policies. But the confluence of forces of the past 50 years is making it easier for liberals to be elected, and change America further.

Because they are almost shut out of the knowledge-making industries of media, culture and the academy, conservatives must make a greater effort to get their message across. To do this, they must shed their axiomatic fear that newcomers will negatively affect the culture, lest it becomes a self-fulfilling prophesy.

Theirs should be an upward mobility message. Or, to use less wonky and more aspirational language, they should speak of attaining the American Dream. But they have to be aggressive, too, in showing that many of the political and cultural changes brought in by the 1960s have erected roadblocks that bar Hispanic success.

That means showing how minoritizing these new immigrants under the “Hispanic” bureaucratic label has hurt Hispanics, rendering them dependent on government for their success.

The sexual revolution heralded what Kay Hymowitz of the Manhattan Institute calls “the unmarriage revolution,” eroding one of the mainstays of Hispanic stability, the family. The rise of government assistance, which the bureaucracy unstintingly pushes on Hispanics, also chipped in. As Charles Murray of the American Enterprise Institute, discovered long ago, welfare undermines the family.

And so today the Hispanic out-of-wedlock birth rate is a stratospheric 53 percent, second only to the African-American rate of 72 percent. This is worrying, as the rate stands upstream from other pathologies.

With education, the prescriptions are easy: school choice is already popular among Hispanics; conservatives should unite with them to fight the teachers’ unions standing in the way. Putting the family together is far tougher, many argue. But it’s not impossible. Politicians should use their bully pulpit to underscore its importance to success.

None of the usual nostrums from the left or the right will help Hispanics, or our country, unless conservatives first grasp that we have undergone a perfect storm in the past 50 years.

Mike Gonzalez, a senior fellow at The Heritage Foundation, is the author of the book “A Race for the Future: How Conservatives Can Break the Liberal Monopoly on Hispanic Americans,” which will be published Sept.2.